Panel-board and panel-board construction



March 21, 1933. F, TT 1,902,790

PANEL BOARD AND PANEL BOARD CONSTRUCTION Filed March 25, 1929 5Sheets-Sheet l March 21, 1933. F STARRETT' 1,902,790

PANEL BOARD AND PANEL BOARD CONSTRUCTION Filed March 25, 1929 5Sheets-Sheet 2 gmllmu Z4 I M, M ,U H m 1 12 26 i LZZJWZZV {gr I March21, 1933. H, R T 1,902,790

PANEL BOARD AND PANEL BOARD CONSTRUCTION Filed March 25, 1929 5Sheets-Sheet 5 A. v x

M nzzyeflwi March 21, 1933.

H. F. STARRETT PANEL BOARD AND PANEL BOARD CONSTRUCTION 5 SheetsSheet 4Filed March 25, 1929 [My/mg March 21, 1933.

F. STARRETT PANEL BOARD AND PANEL BOARD CONSTRUCTION Filed March 25,1929 5 Sheets-Sheet 5 Patented Mar. 21, 1933 PATENT OFFICE BIND-Y .l'.STABBETT, OI CHICAGO, ILLINOIS PAIR-BOARD 1ND PANEL-BOARD OONSTBUGIIONApplication filed Iarch 25, 1929. Serial No. 849,822.

This invention relates to improvements in panel-boards and panel-boardconstruction, and more particularly to that type of panelboard which isequipped with a dead front;

that is, a panel-board of the type in which all the current andpotential-carrying conductors are enclosed so as to prevent accidentalcontact therewith and consequent electrical shock.

More articularly, this invention relates to a panel-board of this typewhich is equipped with switches of the circuitbreaking type; that is,switches with which fuse protection is not necessary, the switchconstruction per se being such that it will open the circuit when it isexposed to overload currents.

One of the objects of this invention consists in the production of animproved and simplified construction whereby a very efiicientpanel-board is obtained and in which construction the mounting spacenecessary for the switches, bus-bars and other currentcarryingconductors is minimized, so as to obtain a very compact as well asefiicient structure.

Another object of the invention resides in using the mounting for theswitches together with the mounting plate for the switch mounting baseand bus-bars so as to provide housings which are completely insulatedfor the panel-board feed bus-bars.

Another object of the invention resides in a special construction of theswitch mounting base whereby it will provide the necessary air gap andpotential creeping surfaces between the current-carrying conductors andmetallic parts of the structure with a minimum amount of mounting basewidth and whereby the switch mounting bases are so de signed that thesaid bases can be readily removed from the panel-board mounting platewithout removing the panel-board trim, and whereby the switch mountingbases together with the covers for the switch serve the dual purpose ofa switch mounting and a barrier constituting one wall of the wiringgutter.

Other objects and features of this invention will become apparent fromthe following description and appended claims.

For the urpose of disclosin this invention one em ent thereof isillustrated in the accompanying drawings, in which:

Figure 1 is a front elevation of a cabinet and panel-board embodyingthis invention, parts being broken away to disclose more ally theinterior construction;

Fig. 2 is a front elevation of the panelboard with the panel-board trimand door removed;

Fig. 3 is a front elevation of the panelboard proper with parts brokenaway, illustrating the manner of mounting the switches. and bus-bars onthe panel-board mounting base, etc.

Fig. 4 is a cross-section taken on'the plane indicated by the line 4-4of Fig. 3 looking in the direction of the arrows;

Fi 5 is a longitudinal cross-section of the pane -boa rd proper taken onthe lane indicated by the line 5-5 of Fig. 3 looking in the direction ofthe arrows;

Fig. 6 is an illustration in rspective of the switch mounting base unitshowing in detail the top construction of said base;

Fig. 7 is an illustration in pers tive of the switch mounting'baseillustrating in detail the bottom construction of said base;

Fig. 8 is a front elevation of a panel-board unit with parts thereofbroken away and fitted with an additional unit for providin fuseconnections to the current-carrying and supplying bus-bars; and,

1g. 9 is a front elevation of the panelboard proper rovided with anadditional unit to supply ses and a switch for the current-carrying andsupplying bus-bars.

The construction illustrated comprises a cabinet or panel-board box 10constructed of sheet steel, or other similar material, equipped withfour sides and the bottom 11. This bottom 11 is equipped with fourmounting screws such as 12 having the head on the under side of thebottom 11 and the screw threaded end thereof extending upwardl towardthe panel-board proper. Loosely tted on each of these screws over thebottom 11 are the washers 13, over which are secured the adjustablethreaded mounting discs 14. These discs 14 provide means for mountingthe pahel-board mounting plate 15 in parallellsm with the wall in whichthe panelboard cabinet is to be positioned. Frequently these walls arenot exactly true and the angle of the wall can be obtained for themounting plate 15 by positioning the mounting discs 14 on theirrespective screws 12 in such position that the plate when solidlysecured on these mounting discs by nuts such as 16 will lie in the sameplane as the wall in which the anel-board is mounted.

The mounting plate 15 is preferably made of steel, although any othersuitable material may be used. This steel plate carries the busbars andthe branch switch mounting bases and can be removed and placed in thecabinet board box as a unit with all the circuit-controlling apparatusmounted thereon, as clearthe movab with the stationary contact 23; themovable 1y illustrated in Figs. 3 and 4.

The branch switch mounting bases such as 17 are secured to the sheetsteel mounting plate 15 by screws such as 18 and 19. These screws 18 and19 are so located as to be readily accessible from the front of theboard so that a branch circuit switch with its mounting base can bereadily removed with-. out disturbing any of the remainder of theapparatus on the panel-board, the screws being accessible by merelyremoving the branch circuit switch cover, such as 20, and anintermediate cover, such as 21, positioned between the covers of thebranclt circuit switches aligned on either side of the mountin base 15.

he circuit-breaking switchsecured to the switch mounting base 17 can beany type of commercial circuit-breaking switch and does not constitutean part of this invention. The specific switc illustrated in thedrawings, and particularly in Fig. 3, comprises e switch contact 22cooperating contact bein actuated by the switch lever 24. The switch isprovided with a coil 25 which, together with a thermostatic element,serves to actuate an armature to automaticall open the switch when acurrent overloa is flowing through the circuit. A further description ofthe switch is unnecessary as the switch does not constitute any part ofthis invention.

This switch is mounted upon the base 17, illustrated in detail in Figs.6' and 7. As shown in these figures the base is provided with themounting holes 26 and 27 which receive the mounting screws 19 and 18,respectively, for securing the switch to the mounting plate 15. The.base is provided with a cut-out portion 28 which serves as a channelthrough which bus-bars 29 or 30 are carried.

The mounting base is equipped on its top face over the cut-out portion28 with a perforation 31. In this perforation is secured the depressedpart of a current-carrying bar 32 with its lower face flush with the topface of the cut-out portion or channel 28.. That ortion of thecurrent-carrying bar 32 whic is positioned in the perforation 31 isfitted with a hole 33 which receives a screw 34 for securing a bus-bar,such as either 29 or 30, to the current-carrying bar 32.

The movable contact 23 of the switch connects the bar 32 to thecurrent-carrying bar 34 through which the current from the busbar iscarried to the branch line terminal 35, by way of the current-carryingbar 36. The branch line terminal 35 is positioned in a cut-out portion37 in the mountin base 17.

As illustrated in Figures 6 and the cutout portion 28 which serves toform the busbar channel does not extend to the bottom face of the branchswitch mounting base 17 but terminates short of this base, sothatanother channel 38 is formed in the branch switch mounting base.

This channel 38 is provided to form a housing for an" insulating plate39 (Fig. 3) which is held in position on the steel mounting plate 15 bythe side walls 40 and 41 of the channel 38, the insulating base 42 atthe top of thepanel-board and the insulating base 43 at the bottom ofthe panel-board. It will consequently be apparent that the side walls 40and 41 of the channel 38 of the several switch mounting bases, togetherwith the insulating in conjunction with said plate 39 serve to form aninsulated housing for either the busbars 29 or 30. This housing for thebus-bars 29'is clearly illustrated in Figs. 4 and 5.

Referring to Figs. 2, 3 and 6, it will be observed that the conductingbar which connects with the branch line terminal 35 is given an angle ofinclination toward the center of the mounting base. This angle ofinclination toward the center of the base is provided so as toincorporate in the construction the necessary surface bemetallic partsof the construction, so, as to prevent creeping of potential, also toincorporate the necessary air distance between conducting parts so astoprovide the necessary air insulation.

The base 17 on its lower surface is liketween the conducting bar and theother wise equipped with the cut-out portion 50 which is provided sothat the necessary creeplng surface will be incorporated in thisconstruction between the branch line terminal and the mounting base 15.By providing mounting base 17 can be minimized and the required creepingsurfaces as well as the necessary air insulation between metallic partscan be maintained. 7

As illustrated in Figs. 1, 2 and 3, these mounting bases 17 are mountedside-by-side on either side of the metal mounting plate 15. When thusmounted the cut-out portions 28 in each mounting base, as hereinbeforedescribed, provide the channel for the bus-bars 29 or 30. The'bus-barswhen positioned in this channel can be directly connected to theconducting bar 32, since this bar is fitted into the perforation 31so'that it will directly contact with the bus-bars 29 or 30, to eitherone of which it maybe directly connected b a screw such as 34. Thisinterconnection etween the conducting bar 32 and the bus-bar serves toosition the bus-bar in place in its insulate housing or channel, andlikewise serves to make a solid contact between the conducting bar 32 ofthe switch and one of the bus-bars, either 29 or 30.

As illustrated in Figs. 3 and 4, it is sometimes essential to stiffenthe mounting plate 15. This becomes necessary when a large numberof'branch line switches are to be mounted on this plate. Fig. 3illustrates a anel-board which is broken at51 and it will obvious thatintermediate this break any number of, branch line switches may bemounted. When a large number of such switches are mounted on the base itmay be stifi'ened by means of a metal strip 52 which extends over thatportion of the length of the mounting plate 15 on which the branch lineswitches are mounted.' Thestrip 52 is secured to the mounting plate 15by means of screws such as 53; the strip being mounted on washers suchas 54.

Secured to this strip 52 are a plurality of -metallic bars such as 55which extend upwardly and are provided at their upper ends with theturnover portion 56 which serves to receive a cover-plate 21, which ismounted on the part 56 by means of screws such as 58.

When the strip 52 is not used the bars 55 are" secured directly to theplate 15.

This cover plate 21, together with the cover 59 for each of theswitches, serves to make the panel-board a dead front board for that.part of the apparatus which contains the branch line switches and thebusbar connections to said switches.

Mounted at the top of the steel mounting plate 15 is the insulating base42 which carrie's the line terminals 60 constituting the branch lineconnection for. the other side of each branch line circuit. These branchline terminals 60 are secured on a bus-bar 61 to which is connected theother terminal of the main line circuit by means of the lug 62 which inturn is connected to the lead from the other side of the line.

The base 42 carrying the bus bar 61 and the line terminal 60 is enclosedin the insulated cover 63. This cover is held in position by means ofscrews 64 which are threaded into the upper portion of bars 65 in turnsecured to the base 42 inany convenient manner. (See Fig. 5.)

The bus-bars 29 and 30 are connected to terminal lugs 68 and 69 by anysuitable means, as, for example, the nuts 1y. These ends of the bus-bars29 and 30 together with the terminals 68 and 69 are mounted on theinsulating bwe 43, and this base together with the ends of the bus-barsand the terminals are enclosed in the housing 74. The housing 74 issecured in position by the screws 75 which are threaded into the upperpart of the uprights 76, the lower ends of O and 71, respectivewhich aresecured to the. insulated base 43 in any suitable manner.

Itwill be evident Zrom this description that I to position an insulatingstrip on the base 15, a an together with said strip serve to enclose thebus-bars feeding the branch line switches in an insulated housing. Themounting plate 15 is likewise equipped. with the insulating base 43which carries the terminals for the bus-bars and the insulating base 42which carries the bus-bar for the second terminal of the branch linecircuits. Each of the branch line switches is provided with aninsulating cover such as 20, the base 42 with an insulating cover 63,and the base 43 with an insulating cover 74. The covers 63, 74 and theswitch covers 20 and 21 serve to completely enclose all thecurrent-carrying conductors on the panel-board and unite to make thepanel-board a dead front panelboard. Moreover, any one of these switchcovers 20 and cover 21 or the covers 63 and 74 for the terminalmountings 42 and 43 respectively, can be removed independently of therest of the equipment so as to give access to the equipment thereunderif necessary.

It will also be evident that the peripheral edge of the cover plates 20for the switches together with the cover plates 63 and 74 for the bases42 and 43, respectively, constitute for the switches and mounting bases42 and 43, respectively, and the outer wall of the cabinet orpanel-board box 10.

From the above description it will be apparent that the branch switchmounting base is so constructed as to serve a plurality of purposes andthat the cover lates or housings for the branch switches, or themounting base for the bus-bars 61 and the mounting base'for theterminals of the bus-bars 29 and 30 serve not onlyto enclose thecurrent-carrying conductors of these devices but also unite to providean insulating wall which constitutes a barrier-wall for a wiring gutter.

Moreover, it will be apparent that the mounting screws 18 and 19 foreach of the branch line switch mounting bases are sojpositioned thatwhen the cover 20 for said switch and the intermediate coverplate 21 areremoved they are readily accessible and the base together with thebranch line switch can then be removed from the panel-board by removingthe mounting screws 18 and 19 and the screw 34 which secures theconductingv lug 32 to either bus-bar 29 or 30.

Vith this character of construction, therefore, in case of trouble withany part of the equipment on the panel-board, the part affected can bereadily removed, repaired and replaced without in any way molesting therest of the equipment of the panel board. This, obviously, makes a veryflexible construction.

The intermediate cover 21, as illustrated in Figs. 1 and 2, is equippedwith designation plates such as 80. These designation plates are made ofany suitable material and are secured to the cover 21 by screws, rivetsor in any other well known manner. 7 The plates are equipped on eitherside with a'turnedover edge so that they will readily receive and holdthe ordinary card or strip on which the circuit designation isdisplayed. One end of each of these designation plates 80 is formed inthe shape of an arrow such as 81, the purpose of which arrow is to pointto the particular branch circuit with which the designation isassociated. The designation plates are so located on the cover 21 sothat one points to the switch on the left side of the panel-board andthe next one tothe switch on the right side of the panel-board. Eachbranch switch cover 20 has placed thereon the designations On and OK toindicate the condition of the switch mechanism to the operator actuatingthe operating lever of the switch 24 when the cover is in position. Withthese designations placed on the covers 20 and 21-. the condition of allthe circuits in the panel-boards will be readily apparent to theobserver from an inspection of the front of the board.

the bus-bar 61 and its associated connections, this can be readilyobtained without molesting any of the panel-board connections orapparatus by merely: removing the screw 64 and the cover 63. ikewise, 1faccess is desired to the bus-bar line terminals 68 and 69,

this can be obtained merely by removingrthe screw and the insulatingcover 74.- his does not in any way molest the rest of th f .I a. 5esired to equip a panel-board,

panel-board equipment. I

When it is such as illustrated in Figs. 1 to 5, with fuses for thebus-bars, the terminal 43, its cover plate 74 and associated equipmentis not used and in place thereof the unit 84 is utilized. e

(See Fig. 8) This unit comprises a base 85 on which are mounted the fuseclips 86, 87, 88

and 89. The fuse clips 86 and 88 are'connected to the bus-bars 29 and 30by an suitable means such as the nuts 90 and 91 whereas the lineconnections are electrically connected to the fuse clips 87 and 89 bysuitable means such as the nuts 92 and 93 which'are positioned on thelateral projections 94 and 95 of the clips 87 and 89, respectively.

When a fuse connection for the bus-bars 29 and 30' is desired with apanel-board construction such as illustrated in Figure 8, it preferablyfitted with a cover 96 which is equipped with a door 97 whichcan bereadily opened to give access to the fuses 98 and 99 secured between the.fuse terminals.

The only difference in the construction illustrated in Figure 8 fromthat shown in.

Figs. 1 to 5, inclusive, is that the bus-bar terminal 43 and itsassociated equipment and cover 74 of Figs. 1 to 5 is replaced y the base84 and its associated equipment and cover.

Likewise, if it is desired to use with the panel-board a fused bus-barconnection as well as a panel-board switch for controlling the flow ofcurrent through the bus-bars, then' the unit 84 and associated equipmentof Fig. 8 is replaced by the unit 100 and associated equipment of Fig.9. This unit 100 contains fuse clips 101, 102, 103 and 104 which aresecured to a terminal 105 in the same manner as this same apparatus isconnected to the terminal 85 of Figure 8.

Connected to the fuse clips 102 and 104 are the conducting bars 106 and107 which in turn are electrically connected to the conducting bars 108and 109 with which two of the movable contacts 110 and 111 of anysuitable switch connect. The other ends of the movable terminals 110 and111 of the switch connect with the contact bars 112 and 113 which, inturn, are connected by means of the nuts 114 and 115 with the lineterminals.

The fuse connections as well as the switch '116 and its associatedcontacts are mounted on a suitable insulating terminal and are protectedby a cover plate 117. Secured to this cover plate by. hinges 118 and 119is a cover 120 which may be raised to give access to the fuses 121 and122 interconnecting the fuse clip terminals 103 and 104 and 101 and 102,respectively.

Any suitable t of switch and fuse connection can read 17; be used withthe panelboard positioned a ove the unit base 100 and if-desired theswitch operating mechanism can be so inter-related with the hinged door120 of the fuse chamber that an interlocking will result whereby thedoor 120 cannot be opened when the switch is in its closed posit1on andthe switch cannot be closed when the door 120 'is in its open positiomAny one of the well known commercial mechanisms for accomplishing thisresult may be utilized and the particular character of switch and fuseconnection per so used with the anel-board does not constitute any partof t invention.

The conducting bars 112 and 113 together with the nuts 114 and 115associated therewith for connecting the line connections to the outsideterminals of the switch 116 are protected by an insulating covering 125which is secured to the base in any suitable manner, preferably in themanner illustrated in Fig. 5 for the insulating cover 74. When thismethod of connection is utilized this cover can be put into position orremoved through the agency of the screws 126 and 127 so as to expose theconducting bars 114 and 115.

A se arate cover plate 125 is provided at the end of the unit 100 sothat the line terminals 114 and 115 will be readily accessible to makethe line connections by merely removing the cover plate 125 and notmolesting any of the rest of the equipment on the board. If thisseparate cover plate 125 were not provided it would be necessary toremove the plate covering the fuses 121 and 122, as well as the switch(116) connections, and this would be necessary every time, itbecamedesirable to inspect the line connections.

By using the separate cover plate 125 the fuse and switch connections donot have to be exposed and the conducting bars 113 and 112 with theassociated nuts 114 and 115 for receiving the line wires are easily andrapidly exposed for inspection or for other purposes by merely removingthe cover 125.

' From the foregoing description it will be apparent that the improvedpanel-board construction herein described com uses a very flexible unitin which any of t e apparatus mounted on the board is readily accessibleby merely removing a small cover plate wh ch exposes only that part ofthe apparatus which it is desired to remove or inspect; that thepanel-board proper, as illustrated in Flgs. 1 to 7, is designed andconstructed so as to minimize mounting centers and utilize cilicientlyall the insulating materials incorporated in the construction, whichrovides the necessary insulating covers for us-bars and switchconnections, and the proper spac ings between current-carryingconductors and metallic parts, so that the essential air gaps andpotential creeping surfaces will be maintaine throughout the equipment.

Moreover, by using the equi ment illustrated in Figs. 1 to 5, and mere yreplacing the terminal 43 and its associated equipment by either a unitsuch as illustrated at 84 on Fig. 8, or at 100 on Fig. 9, thepanel-board 'materially reduce the ultimate dimensions of thepanel-board because of the reduction of mounting centers between therespective branch line circuits. 1

Obviously the invention is not limited to the preferred form thereofwhich is herein illustrated and described butis capable of manyvariations and modifications without departing from the spirit and scopeof the invention as set forth in the following claims.

What is claimed is:

1. A panel-board comprising, in combination, a panel-box enclosure, ametallic panelboard mounting plate positioned in said box, insulatedbranch switch mounting bases secured thereto, a strip of insulatinmaterial positioned on said plate, a steppe longitumal channel formed bythe assembled switch mounting bases, the wider stepped channel servingto laterally position said insulating strip, and a panel-board bus-bar,said bus-bar being channe 2. A panel-board comprising, in combination, apanel-box enclosure, a metallic panelboard mounting plate positioned insaid box, insulating branch switch mounting bases secured thereto, astrip of insulating material positioned on said plate, a steppedlongitudinal channel formed by the assembled switch mounting bases, apanel-board bus-bar, the narrower stepped channel and said insulatingbases serving as an insulated channel to enclose said bus-bar.

positioned in the narrower stepped 3. A panel-board comprising, incombina- I tion, apanel-box enclosure, a metallic panelboard mountingplate positioned in said box, insulating branch switch mounting'basessecured thereto, a stri of insulating material positioned on said ate, astepped longitudinal channel formed by the assembled switch 'rnountingbases, the wider stepped channel of said plate, branch line switchessecured bases, an insulating cover line switch, supporting to saidmountin for each "branc means extendin upwardly from said plate nation,a panel-box enclosure,

and an insulating cover 'tioned 'inter mediate 'said longitudina 'rowsof: line switches and mounted on said supporting means." v j 5. Apanel-board comprising, in combi insulated branch switch mounting basessecured in two longitudinal rows in said enclosure, branch.

line switches secured to said mounting bases, an insulating cover foreach branch lme switch, an insulating cover positioned mtermediate saidlongitudinal -rows of line switches, and mounting screws for securingsaid bases in said enclosures accessible from the front of the board,one of said screws being positioned under the line switch cover,

and the other of the screws being positioned under the intermediatecover. 7

6. A panel-board comprising, in combination, a panel-box enclosure, ametallic panelboard mounting plate positioned in said box, insulatingbranch switch mounting bases secured thereto, a metal reinforcin strisecured to and extending along the; ace 0 said mounting plate, mountingmeans positioned on said strip and an insulating cover'plate secured tosaid means for enclosing the area between said mounting bases. 4

7. A panel-board comprising, in combination, a panel-boxfenclosure, ametall1c panelboard mounting plate positioned n said box, insulatingbranch switch mounting bases secured thereto, a metal reinforcing stripsecured to and extending along the face of said mounting plate,current-carrying conductors secured to'said bases, mount means ositionedon said reinforcing strip, insulatmg housings for said mounting bases,and an insulating cover plate secured to sa1d means, said housings andsaid cover plate forming a dead front for the area of said board inwhich the said bases are situated.

8. A panel-board comprising, in combination, a panel-box enclosure, ametallic panelboard mounting plate positioned in said box, insulatingbranch switch mounting bases se-' cured thereto, insulating housings forsaid switch mounting bases, an insulating termi-. nal base, a lineterminal bus-bar mounted thereon, a second insulating terminal base,

panel-boardbus-bars, terminals for said busswitch for a bars mounted onsaid second base, and in dividual insulating housings for each of saidbases. v

9. A panel-board comprising, in combination, a panel-box enclosure, ametallic anelboard mounting plate positioned in sai box,

insulating branch switch'mounting bases secured thereto, insulatinghousings for each of said switch mounting bases, two insulating bases,each adapted to" carry bus-bar termmal equipment, insulating housingsfor each of said branch switch mounting bases and said terminal bases, awiring gutter sur rounding said mounting late, the said insulatinghousings for said terminal --mounting bases and said branch-switchmounting bases combining to form one continuous wall for sa1d wiringgutter.

i 10. A panel-board comprising, in combination, a anel-box enclosure, apanelboard mounting plate positioned in said box, insulating branch lineswitch mounting bases secured thereto, an insulatin bus-bar terminalbase positioned at eac end of said mounting plate, a wiring guttersurrounding said mounting late, and separate individual .jinsulatingousings for each of saidbases, the said insulating housings for all ofsaid bases combining to form one continuous wall for said wiring gutter.v

11. A mounting for a current-controlling panel-board comprising aninsulating base aving a stepped channel in its lower. face, an insulatinplate positioned in the lower step of sai stepped channel, said plate,togetherwith the upper channel, serving to form an insulated housin forcurrent-carrying conductors feeding the board. Y

' 12. A mounting base for a current-controlling switch for apanel-board, comprisin an insulating base, a branch line termini, adepression in said base in which said branch line terminal ispositioned, a terminal member connected to said branch line terminal,said terminal member being out of contact with said base for a portionof its length for the purpose of increasing the potential creepingsurface between said terminal and other metallic parts -on which thebase may be mounted.

13. A mounting base for a current-controlling switch for a panel-board,comprising an insulating base, a branch line terminal, a depression ofsaid base in which said branch line terminal is positioned, a terminalmember connected to said branch line terminal, said terminal memberbeing shaped so as to be out of contact with said base for a portion ofits length, a cut-out portion located on the bottom of said baseopposite the said depression whereby the length of the'po'tentialcreeping surface from the terminal to the metallic parts on whichthe'base may be mounted is increased.

panel- 'iis ' panel-board bus-bar,

i said plate, .a longitudinal 14. A panel-board comprising, incombination, a panel-box enclosure, a metallic panel-board mountingplate positioned in said box, insulating ranch switch mounting basessecured thereto, a strip of insulating material positioned on said plateand held in place by said bases, a anel-board bus-bar and meansassociated wit said bases for 'securingsaid bus-bar in said insulatinstrip. 7

15. A pane -board comprising, in combination, a panel-box enclosure, ametallic panel-board mounting plate positioned in said box, insulatingbranch switch mounting bases secured thereto, a strip of insulatingmaterial, means in said bases for securing said strip on said plateunder said bases, a and means associated with said bases for securingsaid bus-bar to said bases inposition above said insulating strip.

16. A panel-board comprising, in combination, a panel-box enclosure, ametallic panel-board mounting plate positioned in said box, insulatingbranch switch mounting bases secured thereto, current controllinapparatus secured to said mounting bases at ove channel formed byposition above the assembled switch mounting bases above said plate, aninsulating stri positioned on said plate in said channel, an d bus-barositioned in said channel above said insu ating strip. 1

In witness whereof, I have hereunto subscribed my name.

HENRY F. STARRETT.

a panel-board

